It is not an airsoft, but there is a neat little CO2 BB pistol that is a replica of the M&P. I use it to shoot in my garage when I can't get out to the range. The cost is way low and the trigger is terrible, but it is better than not getting to shoot. I use it for fundamentals only such as dot drills, etc. Unfortunately, the backstrap is not removable.
Here's the link to it at Sportsman's Guide: http://www.sportsmansguide.com/net/cb/sw-mp-air-pistol.aspx?a=455798
Just a thought. Hard to beat for $40.
Good luck!
Kyle
DocMcG
There actually is a airsoft version of the M&P. The one you have is the .177 bb version. Here is what I have.
http://www.pyramydair.com/s/m/Smith_and_Wesson_Spring_M_and_P_40/1573
I think that it is a pretty good air soft gun. It has a long trigger pull but that will make your real gun seem that it has a very nice trigger pull. The only con about it is that after a little while, the magazine will start to leak when you try to put a new CO2 cartridge in. But you can always buy new magazines.
Thanks I will take a look at those